New Delhi: Neither the doctors nor the cancer patients undergoing chemotherapy know for certain whether their body will respond to the treatment.

But now, scientists have developed a new system that can identify which breast cancer patients will respond to chemotherapy within two weeks of beginning the treatment.

The system simultaneously generates 3D images of both breasts and allows researchers to study the blood flow in the breasts, see how the vasculature changes, and how the blood interacts with the tumor.

"There is currently no method that can predict treatment outcome of chemotherapy early on in treatment, so this is a major advance," said Andreas Hielscher, a professor at Columbia University in the US.

"This helps us distinguish malignant from healthy tissue and tells us how the tumor is responding to chemotherapy earlier than other imaging techniques can," said Hielscher.

Neoadjuvant chemotherapy, given for five to six months before surgery, is the standard treatment for some women with newly diagnosed invasive, but operable, breast cancer.

The aim of neoadjuvant chemotherapy is to eliminate active cancer cells – producing a complete response – before surgery.

Those who achieve a complete response have a lower risk of cancer recurrence than those who do not.

However, fewer than half of women treated with neoadjuvant chemotherapy achieve a complete response.

"Patients who respond to neoadjuvant chemotherapy have better outcomes than those who do not, so determining early in treatment who is going to be more likely to have a complete response is important," said Dawn Hershman, leader of the Breast Cancer Programme at the Herbert Irving Comprehensive Cancer Center in the US.

"If we know early that a patient is not going to respond to the treatment they are getting, it may be possible to change treatment and avoid side effects," said Hershman.

The researchers had suspected that looking at the vasculature system in breasts might hold a clue. Breast tumors have a denser network of blood vessels than those found in a healthy breast.

Blood flows freely through healthy breasts, but in breasts with tumors, blood gets soaked up by the tumor, inhibiting blood flow. Chemotherapy drugs kill cancer cells, but they also affect the vasculature inside the tumor.

The team thought they might be able to pick optical clues of these vascular changes since blood is a strong absorber of light.

The researchers analyzed imaging data from 34 patients with invasive breast cancer between June 2011 and March 2016.

The patients comfortably positioned their breasts in the optical system, where, unlike mammograms, there was no compression.

Researchers captured a series of images during a breath hold of at least 15 seconds, which inhibited the backflow of blood through the veins but not the inflow through the arteries.

The researchers then compared the images with the patients' outcomes after five months of chemotherapy.

They found that various aspects of the blood inflow and outflow could be used to distinguish between patients who respond and those who do not respond to therapy.

"If we can confirm these results in the larger study that we are planning to begin soon, this imaging system may allow us to personalize breast cancer treatment and offer the treatment that is most likely to benefit individual patients," said Hershman.